The invention generally relates to improvements in wheelchairs. Wheelchairs are useful in providing mobility for persons unable to walk. They are formed in various configurations, but today's standard wheelchair is usually formed with a tubular metal frame with a seat stretched on the frame. The frame supports main drive wheels on a tubular member, and secondary wheels are provided for balance and steering. Some chairs are collapsible so that they can be stowed when not in use; some are motorized while others are only manually operable.
More and more facilities are being designed to accommodate persons in wheelchairs. However, it is often difficult with present wheelchairs to accommodate wheelchairs without substantially increasing costs of such facilities. Because present wheelchairs are wide, it is often difficult to move a wheelchair through doors, into toilets, down airplane aisles and into other similar locations. Wider facilities can be built, but oftentimes it is at the sacrifice of area needed for other purposes. Existing facilities are expensive to convert, and in some situations it is considered impractical to provide for the width of a wheelchair, and other accommodations often must be made. For example, airplane aisles are normally too narrow for a wheelchair. A narrower wheeled seat often must be provided for moving a paraplegic in an airplane.
Many wheelchairs are collapsible. However, it is important to have the collapsed size as small as possible. In present wheelchairs, the collapsed size is often quite large because the hubs of the wheels extend outward adding width to the wheelchair, and the cross braces holding the wheels apart often cannot assume a completely collapsed orientation. Some prior art wheelchairs had frame members which could telescope outward as the chair was collapsed. Although some chairs were able to decrease the collapsed width, the height or the horizontal extension of the chair was increased as a sacrifice thereof which increased the size of the wheelchair to be stowed. It is therefore an object of the present invention to provide a relatively narrow wheelchair that does not sacrifice seat space to the user, which can be collapsed more narrowly than prior art devices.
Stainless steel or plated tubular steel is usually used for the frame of wheelchairs because it is necessary for strength. However, metal wheelchairs are very heavy. For example, a standard wheelchair weighs approximately 60 pounds (27 kg), and it is difficult to lift or move one. Metal tubing of the prior art wheelchairs can be bent because of the rigidity of the tubing. This type of damage occurs when the user runs into an object such as a high curb or when the wheelchair is transported in the collapsed condition. Slight bending of the tubes causes misalignment of the wheels resulting in a chair that is difficult to drive. Therefore, even though such chairs are heavy, the frames can easily be bent sufficiently to damage the chairs. It is an object of the present invention to provide for a lightweight chair of substantial strength which will not be damaged when encountering curbs or other objects.
Prior art wheelchairs were often difficult to open and close especially if such opening and closing was being done by the user of the chair. It is an object of the present invention, therefore, to provide a chair which is easy to open and close.
Many prior art wheelchairs that accommodate adults are usually too wide for children, and adult wheelchairs either have to be modified for a child or special child-sized chairs must be built. This is unfortunate because as the child grows, a new wheelchair will have to be purchased or the modifications of the smaller chair will have to be removed and replaced by the standard adult-sized chair components. It is an object of the present invention to eliminate the need and the associated cost burden for different sized wheelchairs of modifications of existing wheelchairs or a substitution of different-sized ones.
Rolling wheels have a tendency to pick up water on wet pavement and throw it upward. This is a problem in prior art wheelchairs where users are frequently splashed with water. It is an object of the present invention to prevent water and mud from being thrown at the user, and it is a more specific object to provide a mud and water guard in the wheelchair frame. Another object is to incorporate the mudguard into the frame so that the wheels do not have to extend outward beyond the frame.
Some persons almost "live" in their wheelchairs. A padded seat is often necessary to prevent sores from developing on the pelvic and thigh muscles. The tissue surrounding the pelvis of those having legs amputated is especially tender and subject to becoming ulcerated. The prior art solution to that problem has been to provide cushioning on the wheelchair seat. However, this has a tendency to raise the center of gravity of the chair by raising the person in the chair. Raising the center of gravity makes the chair more unstable to the possible endangerment of the user. This is especially true to persons having had legs amputated because without legs, the center of gravity of the wheelchair-person combination is initially higher. Raising it higher by the addition of cushions makes the wheelchair even more unstable. It is an object of the present invention to allow for cushioning of the seat while maintaining a low center of gravity. Another problem with cushioning is that it is often necessary to provide less cushioning on certain parts of the seat and a softer surface under sore areas. This can be difficult in prior wheelchairs, and it is an object of the present invention to alleviate the problem. A further problem with cushions is their tendency to slip on the seat. An object of the present invention is to eliminate the slipping problem.
Prior wheelchairs had brakes for preventing all movement of the wheelchair, and some chairs had hill holder features that prevent backward movement of the wheelchair while permitting forward movement. Without such a feature, when the user is driving the wheels and encounters a hill, he must thrust the wheels in the forward direction, release and quickly grab the wheels again at the start of the drive motion, or else the wheelchair will roll backwards. A hill holder allows the user to rest between forward movement and is an additional safety feature. However, in prior art devices, the brake and hill holder were mounted separately at different locations. Their mounting had to be accommodated on the tubes of the frame. Moreover, mounting them on the outside of the frame adds potential width to the frame. The handles also can catch clothing or other objects. It is an object of the present invention to combine the brake and hill holder into one unit with one handle. Another object is to mount the handle within easy reach of the person in the chair, and another object is to have the handle located so that it does not extend outside of the frame.
Persons depend on wheelchairs for freedom. Having a chair that is more mobile is important but having one which offers easy ingress and egress may be equally consequential. For example, it is of little benefit to the user of a wheelchair if the chair provides sufficient mobility to maneuver into a toilet stall if he cannot leave the chair to use the toilet. If egress is easy but the configuration of the chair prevents close approach to the commode, the easy egress is wasted. The frame in many prior art wheelchairs prevented the user from getting close to a commode. It is an object of the present invention to design the chair so that commode access is ensured.
It is often desirable to enter or leave a wheelchair from the side rather than from the front or rear. This has been accomplished in the past by having sides that fold downward or are removable. Sidewalls have been provided so that they can straddle from the seat to a remote location so that the user can slide himself along the extended sideboard. However, these prior art devices have met with certain problems. First, the main wheels often interfered with deployment of the sideboard. Also, the sideboards often had difficulty reaching the remote location because of the projecting width of the wheels and the short projection of the sideboard. It is an object of the present invention to provide a wheelchair which allows for transfer along a side panel to a more remote location. It is another object to provide the chair so that the wheels will not interfere with the deployment of the sideboard.
Another problem of prior art wheelchairs has been in the footrest. Ideally, they should be adjustable both forward and backward and up-and-down. However, this adjustment is often difficult for the wheelchair user to make because the footrests are often out of reach. Therefore, it is an object of the present invention to provide footrests which are adjustable with the adjustment being within reach of the user. It is also an object of the invention to have the footrests being foldable toward the center of the chair when the chair is collapsed so that the footrests do not add length or width to the collapsed chair.
Because the wheelchair is often a person's "home," it is desirable that conveniences be provided for him. For example, one of the objects of the present invention is to provide a tray located within easy reach of the user's arms for supporting food or other materials. In order to save materials and their weight, it is an object to incorporate the tray into other parts of the wheelchair so that the trays's parts perform other functions.
The above specific objects and other objects will be discussed in more detail hereinafter. The present invention also has as its object the construction of a low-cost wheelchair with low maintenance costs. A further object is to provide a chair with molded parts rather than tubular parts that require welding for assembly. Another object of the present invention is to construct the wheelchair so that it is easily cleaned. All of the above objects are met by the present invention, and other objects which are also met will be evident from the remaining description of the invention.